The present invention is a continuation-in-part of my co-pending U.S. Patent Application Ser. No. 611,087, filed Sept. 8, 1975, for Encapsulated Solar Cell Assembly, now U.S. Pat. No. 4,078,944.
As disclosed in the aforesaid copening application, a number of important advantages flow from encapsulating solar cells in an hermetically sealed envelope. The use of the surrounding envelope permits isolation of the relatively delicate solar cell from a hostile terrestrial or space environment. Further, instead of moving the solar cell itself to orient it toward the sun and risk damage to the cell, the envelope in which the cell is fixedly disposed may be positioned instead. The presence of the envelope also permits the solar cell to be surrounded by an inert gas so as to limit oxidation and other chemical reactions. The envelope further permits the circulation of a fluid past the cell to draw heat away from it. Finally, the envelope may be coated to admit solar radiation selectively into the envelope.
Since the area of an individual solar cell is small, the amount of current generated as a result of incident solar radiation is by necessity limited. In order to obtain electrical energy in amount that have practical utility, e.g. currents of a magnitude sufficient to drive electrical apparatus, large arrays of solar cells are ordinarily reguired. Such arrays are not only expensive to build, install and maintain, but their size may also render them impractical for certain applications, e.g. for transport into space, and may thus limit the practical uses of this source of energy.
It is already known to use radiation collectors, such as non-imaging light funnels, in order to concentrate relatively large amounts of incident solar radiation on a solar cell. Such collectors may take various forms, for example a compound parabolic configuration as disclosed in Review of Scientific Instruments, Vol. 37. No. 8, pp. 1094-5 (1966); ibid., Vol. 39, No. 3, pp. 419-20 (1968); and ibid., Vol. 39, No. 8, pp. 1217-8 (1968). The collectors so employed often consist of delicate light-weight material, for example of reflective foil. Hence they too are subjected to damage when exposed to a hostile environment, e.g. dulling of the reflective surface. Further, as with solar cells, damage to the collector may occur as it is moved in order to orient it toward the sun.
Although solar cells as such have been encased in hermetically sealed envelopes, as disclosed by the aforesaid copending application Ser. No. 611,087, now U.S. Pat No. 4,078,944 heretofore a number of technical obstacles, a related primarily to positioning and securing the components inside the envelope have militated against all attempts at encapsulating a solar cell in combination with a collector.